<?php

require_once 'HTMLPurifier/ChildDef.php';

/**
 * Definition that allows a set of elements, but disallows empty children.
 */
class HTMLPurifier_ChildDef_Required extends HTMLPurifier_ChildDef
{
	/**
	 * Lookup table of allowed elements.
	 * @public
	 */
	var $elements = array();
	/**
	 * @param $elements List of allowed element names (lowercase).
	 */
	function HTMLPurifier_ChildDef_Required($elements) {
		if (is_string($elements)) {
			$elements = str_replace(' ', '', $elements);
			$elements = explode('|', $elements);
		}
		$keys = array_keys($elements);
		if ($keys == array_keys($keys)) {
			$elements = array_flip($elements);
			foreach ($elements as $i => $x) {
				$elements[$i] = true;
				if (empty($i)) unset($elements[$i]); // remove blank
			}
		}
		$this->elements = $elements;
	}
	var $allow_empty = false;
	var $type = 'required';
	function validateChildren($tokens_of_children, $config, &$context) {
		// if there are no tokens, delete parent node
		if (empty($tokens_of_children)) return false;
		
		// the new set of children
		$result = array();
		
		// current depth into the nest
		$nesting = 0;
		
		// whether or not we're deleting a node
		$is_deleting = false;
		
		// whether or not parsed character data is allowed
		// this controls whether or not we silently drop a tag
		// or generate escaped HTML from it
		$pcdata_allowed = isset($this->elements['#PCDATA']);
		
		// a little sanity check to make sure it's not ALL whitespace
		$all_whitespace = true;
		
		// some configuration
		$escape_invalid_children = $config->get('Core', 'EscapeInvalidChildren');
		
		// generator
		static $gen = null;
		if ($gen === null) {
			$gen = new HTMLPurifier_Generator();
		}
		
		foreach ($tokens_of_children as $token) {
			if (!empty($token->is_whitespace)) {
				$result[] = $token;
				continue;
			}
			$all_whitespace = false; // phew, we're not talking about whitespace
			
			$is_child = ($nesting == 0);
			
			if ($token->type == 'start') {
				$nesting++;
			} elseif ($token->type == 'end') {
				$nesting--;
			}
			
			if ($is_child) {
				$is_deleting = false;
				if (!isset($this->elements[$token->name])) {
					$is_deleting = true;
					if ($pcdata_allowed && $token->type == 'text') {
						$result[] = $token;
					} elseif ($pcdata_allowed && $escape_invalid_children) {
						$result[] = new HTMLPurifier_Token_Text(
							$gen->generateFromToken($token, $config)
						);
					}
					continue;
				}
			}
			if (!$is_deleting || ($pcdata_allowed && $token->type == 'text')) {
				$result[] = $token;
			} elseif ($pcdata_allowed && $escape_invalid_children) {
				$result[] =
					new HTMLPurifier_Token_Text(
						$gen->generateFromToken( $token, $config )
					);
			} else {
				// drop silently
			}
		}
		if (empty($result)) return false;
		if ($all_whitespace) return false;
		if ($tokens_of_children == $result) return true;
		return $result;
	}
}

